Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
1998
Forfattere
Tor MykingSammendrag
Det er ikke registrert sammendrag
Forfattere
Vincent R. Franceschi Trygve Krekling Alan A. Berryman Erik ChristiansenSammendrag
The bark anatomy of Norway spruce clones that were resistant or susceptible to Ceratocystis polonica, a bark beetle vectored fungal pathogen, was compared. The major difference concerned the axial parenchyma cells, called polyphenolic parenchyma (PP cells) because of their vacuolar deposits. The phenolic nature of the deposits was indicated by autofluorescence under blue light, and immunocytochemical studies demonstrating PP cells are enriched in phenylalanine ammonia lyase (EC 4.3.1.5), a key enzyme in phenolic synthesis. Susceptible clone PP cells occurred as single rows filled with dense deposits. The resistant clone had 40% more PP cells, which occurred in rows two cells thick with individual cells also scattered among the sieve cells, and had lighter deposits. Trees inoculated with fungus were analyzed but a distinct fungal response could not be separated from the general wound response. In the resistant clone, phenolic bodies were reduced in size and density or disappeared completely 12 day after wounding, and PP cell size increased. The susceptible clone phenolics and cell size changed only slightly. These data show that PP cells are active in synthesis, storage, and modification of phenolics in response to wounding, providing a primary site of constitutive and inducible defenses.
Forfattere
Tron Eid Hans Fredrik Hoen Petter ØkseterSammendrag
Det er ikke registrert sammendrag
Forfattere
Sondre Skatter Bohumil KuceraSammendrag
A new theory is presented on the cause of the prevalent directions of the spiral grain patterns found in conifers. The hypothesis is based upon the assumption that spiral grain has a function, i.e. that it represents a growth strategy to ensure survival of the trees. The mechanical function of the tree trunk is placed in focus, that is the ability of the trees to withstand external mechanical loads, mainly from wind. Spiral grain is an optimized growth feature when the trees are exposed to combined bending and torsion. Torsion occurs when the crown is asymmetric in the plane perpendicular to the wind direction. Systematic crown asymmetry, with heavier crowns on the south side, was confirmed by measuring the crown projections on 253 sparsely grown pines; 76.7% of the trees had longer branches on the south than on the north side, and the average length difference was 40.8 cm. By studying wind maps it was seen that most of the coniferous forests have prevailing westerly winds, which, when combined with the crown asymmetry, leads to a prevailing torque. Right-handed spiral grain in the outermost layers of mature trees is proposed to be a strategy to withstand this torque, i.e. to avoid stem breakage
Forfattere
Anne Sverdrup-Thygeson Fred MidtgaardSammendrag
Det er ikke registrert sammendrag
Forfattere
Petter NilsenSammendrag
Det er ikke registrert sammendrag
Forfattere
E. Hellström M. Palo Birger SolbergSammendrag
Det er ikke registrert sammendrag
Sammendrag
The genus Bryomyia comprises altogether eight species in the Palearctic region, including one new species Bryomyia amurensis Mamaev et Økland described in the present article. A revised key to the species of Bryomyia in the Holarctic region is presented.
Forfattere
Karl Hilding Thunes Fred MidtgaardSammendrag
Det er ikke registrert sammendrag
Forfattere
Bernt-Håvard ØyenSammendrag
Det er ikke registrert sammendrag